I would put one of those clips thru that hole on your latch.

Any opening or crevice that you feel uncomfortable with should be fixed. Small pieces of 1 by's can be cut and put on the seams.

Or, if cutting and piecing wood to the gaps is too finicky, hardware cloth across the inside should do.

However, I echo the sentiments of the poster on your other thread - this is a chicken tractor, and not meant for over-nighting except if inside something that gives secure conditions. It CAN be tipped over, and with no bottom, the inside quarters would be more accessible to any predator. I would look into getting/making a very secure overnight house for your hens, and maybe put hardware cloth across the bottom of the tractor, so nothing can get in if it tips, nor by digging under it.

I would get a snap or clip of some kind to put in the hole for the latch.

It looks like a lovely day-time house for your hens, and as though, if you move it every few days, as though they will have varied areas to forage in. I would worry about security, though, the more so since you have had one incident with predators already. I HAVE seen housing that looks less secure than that used as permanent housing for hens, next to woods, but I don't know what level of losses are acceptable to the owners, nor if they have, in fact had any.

A possible, and less expensive in terms of time, compromise might be to run an electric wire at about 6" above the ground, around the perimeter of the whole tractor at night. 2 wires, one at 6" and one at 18" would be surer, as would using a section of the electro-mesh. You could unhook this and roll it up in the day. If you don't want to set up a charger and wires from the house, one of the small solar chargers would work, but might cost more. You can also get small battery-powered chargers. Few predators will go through an electric fence, esp. if you bait it the first while with bits of aluminum foil wrapped around a wire, smeared with peanut butter - they get a definite shock from that!

Thanks. Yes, I know it is a "chicken tractor" but the plans sold it as having a secure coop on the second floor....ARGH! I always pull up the plank at night and lock them up.

Some changes I may make are to:
1) figure out a way to plug up the tiny slits I note in my pictures.
2) put a clip in the latch so a smart raccoon can't open them (i.e.-remember the dinasour in Jurasic park that figured out how to open a door?)

I thought about butting a bottom to the coop..but then the chickens won't be able to dig in the grass....they like to make holes and sit in the dirt.

I am a little worried about an animal DIGGING under and getting to them....but at night....it won't matter as the chickens will be safely on the second floor.

Of course, an animal could dig under during the day, right? We don't have dogs and I'm not sure what other animal would be brave enough to dig in broad daylight. I've only seen the raccoons at dawn and dusk.

Should I be concerned about day-time losses from something digging underneath? This is a problem for any chicken tractor, no?